This invention relates generally to packaging machines for wrapping stretch film around products supported upon trays, and more particularly, to a package wrapping and weighing machine which receives products to be wrapped at a first level infeed station, automatically wraps the products and delivers them to a weighing station above the infeed station such that the wrapped and weighed products can be hand-labeled by an operator positioned at the infeed station.
Trayed products, for example, meats and produce in supermarkets, are presently packaged in a variety of ways. The simplest, least expensive wrapping arrangement for low volume is a hand-wrap station which permits an operator to wrap sections of stretch film manually about products which are then weighed and labeled. Some hand-wrap stations include weighing scales as the wrapping platform to increase the productivity and speed of operation. For higher volumes, wrapping machines are available for wrapping trayed products, with the wrapped products then being weighed and labeled either by hand or by means of automatic weighing and labeling equipment.
In order to conserve space, weighing scales and label printers/appliers have been incorporated into wrapping machines. Examples of one form of resulting packaging system are illustrated in U.S. Pat. Nos. 4,415,048, 4,458,470 and 4,548,024. The packaging systems disclosed in these patents locate a weighing scale in the package infeed at one end of the wrapping machine, and a label printer and applier along the wrapped package outlet at the opposite end of the machine. Another integrated packaging system is disclosed in U.S. Pat. No. 4,543,766 wherein a weighing conveyor extends between a package infeed station and a wrapping station of a package wrapping machine. A label printer is positioned to pass labels to a labeling head incorporated into a package holddown of the wrapping machine such that package weighing and labeling cooperatively interrelate to simplify the operating procedures required for the previously-noted integrated packaging systems.
Unfortunately, the prior art packaging systems, which combine weighing and labeling with a wrapping machine, do not permit the weighing scale conveniently to be used for hand weighing separate and apart from the wrapping operation. This is due to the location or integration of the scale into the wrapping machine such that it is not readily available to the operator. This problem is apparent from U.S. Pat. Nos. 4,458,470 and 4,548,024 which provide an auxiliary scale platter on the side of the wrapping machine adjacent the label printer.
The prior art designs also preclude the possibility of utilizing one of these machines as an intermediate machine between a hand-wrap station and a fully automated packaging system due to the substantial separation of the weighing scales and the label printers. An intermediate machine would permit an operator to automatically wrap and weigh packages, and conveniently hand-label them in a single operation and from a single operating position. Such an intermediate machine would handle volumes between the low volume appropriate for a hand-wrap station and the high volume appropriate for a fully automatic packaging system at a machine cost which would also be intermediate the two.
A potentially more important problem of the noted prior art packaging systems which perform weighing before wrapping and labeling should be apparent upon viewing a typical wrapping machine within a supermarket produce or meat department. Small portions of meat and produce are found on and around the elevators of such machines. By weighing trayed products prior to wrapping, the weights include any product which may fall from the tray prior to or during the wrapping operation. Accordingly, the weights and corresponding prices indicated on the labels which are ultimately applied to the packages are for the full complement of product originally within the tray prior to wrapping even though a small portion may be dislodged prior to or during the wrapping operation. In this event, the prices charged to the consumer are over the actual prices for the product contained within the wrapped packages.
It is thus apparent that the need exists for a package wrapping and weighing machine which can serve the need of packagers whose requirements are between the capabilities of hand-wrapping stations and fully automated packaging systems, which machine also provides for weighing a package after it is wrapped such that labels reflect only true weights, and accordingly, true prices.